1. Field of the Invention
The present invention relates to communication systems and more particularly to a communication system capable of displaying messages comprising a plurality of different scripts.
2. Background Art
Communications systems in general and paging systems in particular using transmitted call signals have attained widespread use for calling selected receivers to transmit information from a base station transmitter to the receivers. Modern paging receivers have achieved multifunction capability through the use of microcomputers which allow the paging receiver to respond to information having various combinations of tone, tone and voice, or data messages. The information is transmitted using any number of paging coding schemes and message formats. The paging coding schemes typically are of the multi-character word length type where the character may be a binary digit or the like. Most prior art paging systems have been able to transmit and receive data message information in only one language, e.g. only in English or only in Japanese. The widespread use of paging systems now requires that data messages comprised of different languages be transmitted to a paging receiver for receiving and displaying the symbols of the languages to the paging receiver user. These languages include alphanumeric languages such as English, French, German or the like as well as ideographic languages such as Japanese, Chinese or the like.
In U.S. patent application Ser. No. 926,289, there is described a paging system in which both alphanumeric and ideographic languages may be displayed. However, the resolution of the display is limited to that conventionally used for alphanumeric languages. Such a display usually has 2 rows of 16 characters where each character is formed on a 5.times.7 dot matrix. Although a 5.times.7 dot matrix is sufficient for most alphanumeric languages, it has a somewhat limited resolution for most ideographic languages. The above mentioned patent describes the use of 5.times.7 dot matrices to display the Japanese Katakana script in a limited resolution. However, it cannot display the Kanji and Hiragana Japanese scripts which require greater resolution. Furthermore, it cannot be used to display Chinese which has a very large number of symbols comprising its language. There are over 3500 commonly used Chinese characters. In order to display such a large number of symbols, the resolution of the display must be increased. A suitable display for these scripts is a 16.times.16 or larger dot matrix display per character.
Naturally, alphanumeric scripts can also be displayed on such a display, however, it will be appreciated that in order to transmit such characters requires longer data words than for the smaller 5.times.7 characters. Indeed, where the 5.times.7 character requires 1 byte of information, a 16.times.16 character requires 2 bytes. Thus greater transmitting time is required for 16.times.16 characters.
In the operation of paging receivers, important factors involved in their successful operation include the portability of the receiver, the limited energy available for the receiver, the amount of memory available for the paging receiver's microcomputer, the limited availability of the radio spectrum, the fast response time required in today's active society and the number of paging receivers included in the paging system. In such paging receivers, in order that the drain on the battery be minimized, the paging receiver is systematically turned off and turned on to maximize the length of time energy is available from the batteries. The limited energy in which the paging receiver must operate limits the memory and minimizes the electronic circuitry such as the display in the paging receiver.